It is studied that water and oil repellency and soil resistance are imparted by treating a surface of a masonry such as stone with a compound having a fluoroalkyl group (Rf group).
For example, JP-A-57-23662 describes that an acrylate having a Rf group is coated on a concrete and a stone to form a protective film. JP-A-07-109317 discloses a treatment agent comprising a fluorine-containing copolymer comprising a monomer having a Rf group, and a silicone-based vinyl monomer. JP-A-11-507687 discloses a masonry-treatment agent comprising a water-soluble polymer having a Rf group, a carboxyl group, an oxyalkylene group and a silyl group. EP1225187 discloses the treatment of ceramics with a polymer having a silyl group which comprises a Rf group-containing monomer, a fluorine-free monomer and a silyl group-containing monomer. Further, JP-A-11-077677 proposes that a stone is treated with a phosphate ester having a Rf group.
These treatments or these treatment agents, however, do not have both of sufficient water repellency and sufficient oil repellency, and cannot impart sufficient soil resistance for a masonry-treatment agent.
On the other hand, a water- and oil-repellent agent and a soil resist agent, comprising a polymer containing a fluorine-containing acrylate substituted at its α-position by a fluorine atom, chlorine atom or the like are disclosed in, for example, JP-A-63-90588, JP-A-63-99285 and JP-A-1-315471. However, these have not been practically used as a masonry-treatment agent.
Described below are the environmental problems raised by perfluorooctanoic acid (PFOA). The results of the latest researches [a report of the Environmental Protection Agency (EPA), “PRELIMINARY RISK ASSESSMENT OF THE DEVELOPMENTAL TOXICITY ASSOCIATED WITH EXPOSURE TO PERFLUOROOCTANOIC ACID AND ITS SALTS”(http://www.epa.gov/opptintr/pfoa/pfoara.pdf)] have taught that PFOA (perfluorooctanoic acid), one of long chain fluoroalkyl compounds, is proved to have a danger to burden the environment. Under such a situation, EPA announced on Apr. 14, 2003 that the scientific investigation on PFOA should be more intensively executed.
On the other hand, the Federal Register (FR Vol. 68, No. 73/Apr. 16, 2003 [FRL-7303-8], http://www.epa.gov/opptintr/pfoa/pfoafr.pdf),    EPA Environmental News FOR RELEASE: MONDAY Apr. 14, 2003 EPA INTENSIFIES SCIENTIFIC INVESTIGATION OF A CHEMICAL PROCESSING AID (http://www.epa.gov/opptintr/pfoa/pfoaprs.pdf) and    EPA OPPT FACT SHEET Apr. 14, 2003 (http://www.epa.gov/opptintr/pfoa/pfoafacts.pdf) have published that telomers have a possibility to produce PFOA when decomposed or metabolized (herein, the telomer means a long chain fuluoroalkyl group), and also that telomers have been widely used in foam fire extinguishers, care products, washing materials, carpets, textiles, paper, leather, etc., in order to impart water and oil repellency and soil resistance to them.